Penttilä J M, Anttila M, Puolakkainen M, Laurila A, Varkila K, Sarvas M, Mäkelä P H, Rautonen N
Department of Vaccines, National Public Health Institute, Helsinki, Finland.
Infect Immun. 1998 Nov;66(11):5113-8. doi: 10.1128/IAI.66.11.5113-5118.1998.
Cell-mediated immune (CMI) responses play a major role in protection as well as pathogenesis of many intracellular bacterial infections. In this study, we evaluated the infection kinetics and assessed histologically the lymphoid reactions and local, in vitro-restimulated CMI responses in lungs of BALB/c mice, during both primary infection and reinfection with Chlamydia pneumoniae. The primary challenge resulted in a self-restricted infection with elimination of culturable bacteria by day 27 after challenge. A mild lymphoid reaction characterized the pathology in the lungs. In vitro CMI responses consisted of a weak proliferative response and no secretion of gamma interferon (IFN-gamma). The number of lung-derived mononuclear cells increased substantially during the primary infection; the largest relative increase was observed in B cells (B220(+)). After reinfection, the number of lung-derived mononuclear cells increased further, and the response consisted mainly of T cells. The reinfection was characterized in vivo by significant protection from infection (fewer cultivable bacteria in the lungs for a shorter period of time) but increased local lymphoid reaction at the infection site. In vitro, as opposed to the response in naive mice, acquired immunity was characterized by a strongly Th1-biased (IFN-gamma) CMI response. These results suggest that repeated infections with C. pneumoniae may induce Th1-type responses with similar associated tissue reactions, as shown in C. trachomatis infection models.
细胞介导的免疫（CMI）反应在许多细胞内细菌感染的保护和发病机制中起主要作用。在本研究中，我们评估了BALB/c小鼠在初次感染和再次感染肺炎衣原体期间肺部的感染动力学，并通过组织学评估了淋巴反应以及局部体外再刺激的CMI反应。初次感染导致了一种自我限制的感染，在感染后第27天可培养细菌被清除。肺部病理表现为轻度淋巴反应。体外CMI反应包括微弱的增殖反应且无γ干扰素（IFN-γ）分泌。在初次感染期间，肺源性单核细胞数量大幅增加；在B细胞（B220(+)）中观察到最大的相对增加。再次感染后，肺源性单核细胞数量进一步增加，反应主要由T细胞组成。再次感染在体内的特征是对感染有显著保护作用（肺部可培养细菌数量在较短时间内减少），但感染部位局部淋巴反应增加。在体外，与未感染小鼠的反应不同，获得性免疫的特征是强烈的Th1偏向性（IFN-γ）CMI反应。这些结果表明，肺炎衣原体的重复感染可能诱导与沙眼衣原体感染模型中相似的Th1型反应以及相关的组织反应。
